A former U.S. Air Force sergeant was arrested Friday in Thailand in the 1994 killing of his pregnant wife, whose battered body was dumped on the side of a road north of Muir Beach in Marin County.

Saner Wonggoun, 59, was based at Travis Air Force Base in 1994, and disappeared shortly after his wife's body was found wrapped in a sleeping bag. He remained in hiding, eluding capture in Thailand, for the past 12 years, authorities said.

Wonggoun, who spent 18 years in the military, was listed by the Air Force as its most-wanted fugitive.

"We have really been pushing the last couple of months to try to find this guy, and we had some really, really hard-core agents in Thailand trying to find him," said Capt. Christine Millette of the Air Force's Office of Special Investigations.

Wonggoun will be court-martialed on charges of premeditated murder and could face the death penalty if convicted, Millette said.

Wonggoun's wife, Sopha, was found Jan. 7, 1994, at the bottom of a hill next to Highway 1. A tourist came upon the body while hiking in a remote area near Slide Ranch north of Muir Beach, said Marin sheriff's Sgt. Mike Crain.

Sopha Wonggoun was 42 years old and eight months pregnant when she was bludgeoned to death. Her body had been wrapped in a sleeping bag and had apparently been rolled down the hill, Crain said.

"We don't know anything about motive," Millette said. "That will all come out in the trial."

Crain said Saner Wonggoun had been the primary suspect from the start.

Wonggoun had lived with his wife and their two children at Travis. Born in Nakorn Nayok province in Thailand, he moved to the United States when he was 21, became a citizen in 1978 and joined the Air Force. He married Sopha Yodpet, also a naturalized citizen, in 1981 and was working as an air cargo supervisor at Travis when her body was found.

Wonggoun disappeared before investigators could arrest him, leaving his two children with a neighbor who had instructions to pass them on to friends, according to Air Force investigators.

"We found his vehicle at the airport," Crain said. "He had bought a one-way ticket to Thailand."

Wonggoun arrived in Bangkok on Jan. 14, 1994, according to investigators, but the trail soon went cold.

Two weeks ago, U.S. authorities began a media blitz in Thailand that included a $27,300 reward for Wonggoun's capture. On Friday, the Royal Thai Police arrested him in Phitsanulok province, 208 miles north of Bangkok, after authorities were tipped to his location.